| Section       | Size (bytes)  | Note                                        |
|---------------|---------------|---------------------------------------------|
| Header        | 8             | 'anim_1.0'                                  |
| Group ID      | 1             | 0 means no group                            |
| Columns       | 1             |                                             |
| Rows          | 1             |                                             |
| Frames        | 1             |                                             |
| Data          | Variable      | (index, flag); Cols x Rows x Frames x 2     |